From f0718ce228cb015daeea848d98e8a757e66fd7d9 Mon Sep 17 00:00:00 2001
From: Steve Mao <maochenyan@gmail.com>
Date: Mon, 8 Apr 2024 21:35:29 +1000
Subject: [PATCH] IsSqlType instance is needed if the field is an array of enum

when toFields is used on sql array, it uses this instance

```
(Default ToFields a (Field_ n b), IsSqlType b) => Default ToFields [a] (Field (SqlArray_ n b))
```

Which cast the value to the enum type
---
 src/Opaleye/Experimental/Enum.hs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/Opaleye/Experimental/Enum.hs b/src/Opaleye/Experimental/Enum.hs
index 83eeeb3f..5fb89bc3 100644
--- a/src/Opaleye/Experimental/Enum.hs
+++ b/src/Opaleye/Experimental/Enum.hs
@@ -83,6 +83,9 @@ data EnumMapper sqlEnum haskellSum = EnumMapper {
 --
 -- instance D.Default O.ToFields Rating (O.Field SqlRating) where
 --   def = enumToFields sqlRatingMapper
+--
+-- instance IsSqlType SqlRating where
+--   showSqlType _ = "mpaa_rating"
 -- @
 enumMapper :: String
            -- ^ The name of the @ENUM@ type